1. Field of the Invention
The present invention relates to a collision determining apparatus for a vehicle that determines a vehicle collision, and causes an occupant protection apparatus such as, for example, an airbag apparatus or a seatbelt pretensioner to be operated.
Priority is claimed on Japanese Patent Application No. 2004-277692, filed Sep. 24, 2004, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, collision determining apparatuses for vehicles are known that are provided with acceleration sensors that, for example, detect the acceleration (or the rate of deceleration) that is applied to a vehicle. These apparatuses detect change in acceleration of a vehicle using acceleration signals that are output from the acceleration sensor, and perform temporal primary integration or temporal secondary integration on the acceleration signals. When these integral values exceed predetermined respective threshold values, an occupant protection apparatus such as, for example, an airbag apparatus or a seatbelt pretensioner is operated.
When it is determined by this type of collision determining apparatus for a vehicle that the vehicle is in a collision, the airbag apparatus, for example, ignites a gas generating agent inside an inflator using a squib so that gas is generated by the inflator. The airbag is then inflated by this gas so as to control any secondary collision between an occupant and components inside the vehicle interior (see, for example, Japanese Unexamined Patent Application, First Publication No. 2003-191817).
In a conventional collision determining apparatus for a vehicle such as that described above, it is necessary for the state of the collision to be determined in a short time from when the collision occurs, and for the operation of an occupant protection apparatus to then be controlled.
However, by simply altering the threshold value for the integral values of the acceleration signals that are output from the acceleration sensor to values that make it easy to determine a collision is occurred, the problem arises that the occupant protection apparatus ends up being operated even when the collision is not so severe as to require the occupant protection apparatus to be operated.